Circular Patch Leaky Wave Antenna for Q-Balanced Beam Sensing
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Solution Overview
Problem
Current leaky wave antenna systems are designed using the Q-balancing method and asymmetric approaches, which fail to achieve circular polarization with frequency-sensitive beams and small beams simultaneously, neglecting essential parameters like mutual coupling, input reflection coefficient, axial ratio, and open stopband suppression.
Innovation Solution
A series-fed patch leaky wave antenna with a circular patch geometry is employed, utilizing the E01 mode for radiation and incorporating a delay loop and circular patch stub configuration to tune reflection coefficient, axial ratio, mutual coupling, and open stopband suppression by adjusting a single parameter, achieving high angle resolution and frequency sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional leaky wave antenna design is used, then basic radiation function is achieved, but essential parameters like mutual coupling, input reflection coefficient, axial ratio, and open stopband suppression are neglected
Solution Approach 1:
The patent incorporates feedback mechanisms through full-wave simulation and iterative optimization processes that continuously adjust design parameters based on performance metrics including mutual coupling, input reflection coefficient, axial ratio, and open stopband suppression. This feedback loop ensures all essential parameters are optimized simultaneously.
Solution Approach 2:
The patent creates a universal design framework that addresses multiple performance requirements (mutual coupling suppression, reflection coefficient optimization, axial ratio control, and stopband suppression) within a single integrated antenna structure, rather than treating each parameter separately.
2Difficulty of detecting and measuring
If radar sensing is implemented for occupant detection and classification, then contactless sensing capability is achieved, but sensor requirements and system complexity increase
Solution Approach 1:
The patent implements a universal radar sensing system using the leaky wave antenna that performs multiple functions including occupant detection, occupancy classification, vital sign monitoring, and seat-belt reminder functionality. This multi-functional approach reduces the number of separate sensors needed and simplifies the overall system architecture.
Solution Approach 2:
The patent utilizes parameter changes in the frequency domain, where the leaky wave antenna's frequency-dependent radiation characteristics enable different sensing functions to be achieved by analyzing signals at different frequencies, thereby reducing hardware complexity while maintaining diverse sensing capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables a large beamsweep over frequency, allowing for high angle resolution and cost-efficient in-vehicle occupant detection and classification, vital sign monitoring, and seat-belt reminder functionality with reduced sensor requirements and complexity.
Implementation Method 1
utilizing the E01 mode for radiation
Implementation Method 2
antenna with frequency dependent radiation directions (e.g. a kind of a leaky wave antenna or meta material antenna), so the antenna can sense into different directions
Data Source
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AI summary
A periodic type leaky wave antenna, formed, e.g. on a printed circuit board, using cells of a filled circular structure. The leaky wave antenna may be formed in a series fed patch configuration. In order to achieve a high quality factor with respect to high frequency sensitive beam, a circular patch structure may be used, giving the best area to perimeter ratio. The cavity model based design considerations yield a proportional Q-factor expression with respect to the geometrical ratio. The antenna design takes into consideration effects such as degradation at broadside and circular polarisation, as well as input reflection coefficient. The tuning of a delay loop length yields a simple optimization criterion in order to achieve Q-balancing, circular polarisation and a matched configuration.